When people speak in English, French, German, Italian, Mandarin, Spanish, Skype will be able to take their spoken words and turn them into a different language. The much-heralded Skype Translator made its debut as a standalone Windows 8 preview app, and was demoed as part of the Microsoft Build event at which CEO Satya Nadella’s words were simultaneously translated and subtitled on the live stream. The technology has been transferred to the main Skype app and is available across six spoken languages – English, German, French, Italian, Mandarin and Spanish – and over 50 written languages for messaging. Only the originator of the call needs to be on Windows for the translation to work — but the person on the other end, if not on Windows, will only hear translated audio and not see the text, a Microsoft representative explained in an email to NBC News. Skype’s translation feature uses machine learning — computers that are built to acquire knowledge like humans, so that they get smarter as time goes on.

For now, Skype only speaks English, Spanish, French, Italian, German and Mandarin Chinese — but if you’re just chatting in text, there are a total of 50 languages available. Initially this will be a Windows desktop only release, but if Microsoft continues to push for platform parity on its features we can expect it to come to Mac, Linux and mobile devices soon. That means that the translations will improve as it is used more, Skype said, and the tools have already come on vastly since they were first introduced through the previews. Mobile and Mac users are out of luck for the present — try Google’s free Translate app instead until Microsoft brings Skype Translator to your platform.

PCMag got some time with Skype Translator’s lead, Lilian Rincon, at Microsoft’s New York offices, and tried out a conversation with an Italian speaker. “Everyone who has seen it is really wowed by it,” said Rincon. “Translator has been decades in the making, it’s one of the hero projects of Microsoft Research.” When asked if third-party technologies were used, she said “it’s all Microsoft tech, from speech detection, translation using natural language learning, and then text to speech.” The same team that works on Cortana’s speech-to-text engine is involved in Skype Translator’s language recognition. When you use Skype Translator’s spoken translation, you’ll still see the speech to text for each side’s language, and there’s a pause between the time one user speaks and Skype renders the other language.

In any event, simply being able to converse with another person and use spoken language and body language to communicate, as Skype’s voice chat does, is pretty magical. For more on the VoIP and videoconference application and service, read PCMag’s full review of Skype for Windows, which will be updated with the Translator information soon.